{% comment %}
# Jekyll Group-By-Array 0.1.0
# https://github.com/mushishi78/jekyll-group-by-array
# © 2015 Max White <mushishi78@gmail.com>
# MIT License
{% endcomment %}

{% comment %} Initialize {% endcomment %}
{% assign __empty_array = '' | split: ',' %}
{% assign group_names = __empty_array %}
{% assign group_items = __empty_array %}

{% comment %} Map {% endcomment %}
{% assign __names =  include.collection | map: include.field %}

{% comment %} Flatten {% endcomment %}
{% assign __names =  __names | join: ',' | join: ',' | split: ',' %}

{% comment %} Uniq {% endcomment %}
{% assign __names =  __names | sort %}
{% for name in __names | sort %}

  {% comment %} If not equal to previous then it must be unique as sorted {% endcomment %}
  {% unless name == previous %}

    {% comment %} Push to group_names {% endcomment %}
    {% assign group_names = group_names | push: name %}
  {% endunless %}

  {% assign previous = name %}
{% endfor %}


{% comment %} group_items {% endcomment %}
{% for name in group_names %}

  {% comment %} Collect if contains {% endcomment %}
  {% assign __item = __empty_array %}
  {% for __element in include.collection %}
    {% if __element[include.field] contains name %}
      {% assign __item = __item | push: __element %}
    {% endif %}
  {% endfor %}

  {% comment %} Push to group_items {% endcomment %}
  {% assign group_items = group_items | push: __item %}
{% endfor %}